The George Zimmerman murder trial began with a prosecutor telling the jury that Zimmerman killed teenager Trayvon Martin "because he wanted to," while Zimmerman's lawyer told the court it was a "sad case" but that "there are no monsters here."

The jury heard several tapes, including Zimmerman's initial call to police as well as 911 calls made by people who heard a fight outside with someone in the background screaming for help.

Trayvon Martin's mother abruptly left the courtroom when the tape with the screams was played in court.

The racially charged case began with fireworks as prosecutor John Guy opening the trial with the blunt and shocking words, "F***ing punks."

Martin's parents wept and Zimmerman sat stoically as Guy described the teenager as an innocent victim minding his own business when Zimmerman confronted him.

The prosecutors laid out a case in the second-degree murder trial against Zimmerman by saying he overstepped his role as a neighborhood watch captain. He argued that he profiled, followed and, ultimately, killed a 17-year-old high school student who was walking to his father's girlfriend's home after leaving a convenience store.

Guy said that after the shooting, Zimmerman lied to police in the days ahead. The jury listened often with their hands clasped together over their mouths.

Defense lawyer Don West in a considerably less fiery opening used a map of the Twin Lakes Retreat Subdivision where Martin was killed. He told jurors about recent crime in the community, and how Zimmerman and others in the neighborhood were instructed to report suspected crime.

"Residents would ask him to phone in something and to report something," said West. "There was an attempted break-in just a couple weeks before."

West played the infamous non-emergency made by Zimmerman to police as he reported a "suspicious" teenager. The jury listened intently as the call was heard in the courtroom.

The lawyer tried to explain away Zimmerman's comments about "these a**holes always get away" as words made not by a man consumed with ill intent, but as someone who had been the point person in a community dealing with rising crime.

In call to police, Zimmerman said Martin stared at him, approached him, had his hands on his waist band and then ran off.

"You will see the evidence proves at least one thing. Trayvon Martin hadn't gone home," said West. "He had plenty of time, but choosing not to do that he either left or just hid in the darkness to see about this guy who was following him and turned out of the darkness and said why are you following me."

West concluded his opening statement by objecting to the frequent description of Martin as being "unarmed." The lawyer said Martin "armed himself with a deadly weapon, a concrete sidewalk" when he allegedly banged Zimmerman's head on the ground.

The defense showed photos of Zimmerman's head bloodied shortly after the shooting, which West said was the result of Martin banging Zimmerman's skull against the pavement, evidence that Zimmerman shot Martin in self defense, he said.

The case that renewed America's long, bitter and polarizing debate about race and guns began with Zimmerman's family o being kicked out of the courtroom as Martin's parents were allowed to stay and watch.

According to Florida law, a victim's family can stay inside a courtroom and watch the proceedings. However, no such rule covers family rights for the accused especially when they are on the witness list. The family attorney for the Martins, Benjamin Crump, was also kicked out of court. It was a bitter start to what has been one of the more divisive cases in recent memory.

"I'm here today as Trayvon Martin's mom as I have been every day. I will be attending every day to get justice for my son," said Sybrina Fulton moments before she and Martin's father walked into court. "I ask that you pray for me and my family because I don't want any other mother to have to experience what I am going through now."

Key to the trial will be determining Zimmerman's state of mind nearly 16 months ago when the shooting took place.

"To prove second-degree murder, prosecutors must prove that Zimmerman was filled with ill-will, hatred or spite," said criminal defense attorney Mark Eiglarsh, who has no connection to the case. "Jurors can consider a lesser charge of manslaughter if they think what Zimmerman did was unlawful but didn't contain those necessary elements."

For the next two to four weeks, the jury might hear from neighbors who saw or heard some kind of struggle between both men on Feb. 26, 2012, and called 911 for help. But none of the potential witnesses saw who initiated the altercation, nor intervened even when one of the two men cried out for help.

Who was howling for help in those 911 tapes might become one of the most important questions to be weighed by the jury of six woman. They will have to decide for themselves after Circuit Judge Debra Nelson banned the testimony of two audio experts who said they could hear Martin begging for his life on those tapes.

After opening statements, the state is expected to begin calling witnesses to the stand. Among those who will eventually testify is a young woman known as W8 who was on the phone with Martin five minutes before he was shot and said the teen was unnerved by and afraid of Zimmerman.

A jury might also eventually watch a re-enactment video filmed by police as Zimmerman, with bandages on his head, recounted his version of events to investigators. Zimmerman gave several video and audio statements to police in the days after the shooting, and his legal team says that might be the reason he never takes the stand in this case.

"At a minimum, what's at stake is a potential life sentence for [Zimmerman], who believes, as do his supporters, that he was the victim, and not Trayvon," Eiglarsh, the attorney, said. "But because of the long history of racial tension in Stanford, Florida, there are many people who believe that the only verdict that speaks the truth, the only justice, is guilty."

The case has gripped and divided the central Florida community of Sanford from the beginning. The Seminole County courthouse instituted a lottery for the public interested in watching the case, and set up protest areas for those looking to vocalize their opinion. But only a handful of protestors showed up during the nine-day jury selection.

The six jurors and four alternates who will hear opening statements are now isolated, away from their homes, with minimal contact with family and friends until the trial ends.

Both sides say sequestration will help eliminate juror exposure to outside influence as this controversial case kicks off. It's one of the few areas of agreement between all sides.